Conventionally, in weft knitting, a basic knitted fabric is knitted in plain knitting in which knitting is performed to form knit stitches. Plain knitting is also referred to as plain stitch. For example, a flat-type flat knitting machine is provided with needle beds that are opposed to each other, and using knitting needles of the mutually opposed needle beds, a knitted fabric in so-called rib knitting or rib stitch can be knitted. Using rib knitting, a knitted fabric can be knitted that is thicker than in plain knitting, in a structure in interlock, milano rib, or the like. In rib knitting, basically, knitting is performed alternately using knitting needles of mutually opposed needle beds for each stitch in the course direction, and a groove and a streak in the wale direction are alternately formed. Interlock provides a structure in which two basic rib knitted fabrics are relatively shifted in the course direction and thus a groove line on one fabric is filled with a streak line on the other fabric, so that the surface becomes smooth. Interlock is also referred to as smooth, double rib, or the like. In milano rib, a knitted fabric for two-course knitting is knitted in which continuously after a course of basic rib knitting, a course of plain knitting is knitted on each of the mutually opposed needle beds.
Even in a plain knitted structure, a thick knitted fabric can be knitted, for example, in moss stitch knitting in which knit and tuck are combined. The applicant has disclosed a thick, less stretched or contracted, and firm knitted fabric knitted by combining plain knitting and transfer knitting (see Japanese Examined Patent Publication JP-B2 7-37699 (1995), for example).
Basically, sewing is not necessary when a knitted product that is to be worn on the human body is knitted, for example, as a tubular knitted fabric having a shape corresponding to wearing portions such as the upper body, the lower body, the arms and the legs. A tubular knitted fabric can be knitted even in a flat-type flat knitting machine, by performing plain knitting on each of mutually opposed needle beds. However, there is a limitation on knitting a structure in rib knitting in order to make at least a part of the knitted fabric thick. An ordinary flat-type flat knitting machine has two front and back needle beds that are opposed to each other, and thus in order to knit a tubular knitted fabric including a rib knitted structure, for example, drawn-off knitting is performed in which odd-numbered knitting needles and even-numbered knitting needles on each needle bed are respectively allocated to the front side and the back side of the tubular knitted fabric. In drawn-off knitting, a knitted fabric feels coarser than the actual gauge number.
As a flat knitting machine, a machine with a larger number of needle beds also has been realized, and examples thereof include a four-bed machine with four needle beds in total in which two beds are provided in each of the front and back portions. With such a flat knitting machine, a tubular knitted fabric including a rib knitted structure can be easily knitted. However, a four-bed machine has a complicated mechanical structure, and thus such a machine is limited.
A structure in moss stitch knitting is inferior in thickness to a rib knitted structure. However, for a rib knitted structure, transferring is necessary in the course of knitting both in the case of performing drawn-off knitting and in the case of using a four-bed machine. Thus, a rib knitted structure requires a complicated knitting process and takes effort. The knitted fabric in JP-B2 7-37699 has a similar problem because transferring is necessary.